Linked Life Data

18474557

Source:http://linkedlifedata.com/resource/pubmed/id/18474557

Statements in which the resource exists as a subject.
PredicateObject
rdf:type
lifeskim:mentions
pubmed:issue
Pt 6
pubmed:dateCreated
2008-5-13
pubmed:abstractText
The family Polydnaviridae is a large group of immunosuppressive insect viruses that are symbiotically associated with parasitoid wasps. The polydnavirus Microplitis demolitor bracovirus (MdBV) causes several alterations that disable the cellular and humoral immune defences of host insects, including apoptosis of the primary phagocytic population of circulating immune cells (haemocytes), called granulocytes. Here, we show that MdBV infection causes granulocytes in the lepidopteran Spodoptera frugiperda to apoptose. An expression screen conducted in the S. frugiperda 21 cell line identified the MdBV gene ptp-H2 as an apoptosis inducer, as indicated by cell fragmentation, annexin V binding, mitochondrial membrane depolarization and caspase activation. PTP-H2 is a classical protein tyrosine phosphatase that has been shown previously to function as an inhibitor of phagocytosis. PTP-H2-mediated death of Sf-21 cells was blocked by the pan-caspase inhibitor benzyloxycarbonyl-Val-Ala-(O-methyl) Asp-fluoromethylketone (Z-VAD-FMK), but cells maintained in this inhibitor still exhibited a suppressed phagocytic response. Mutagenesis experiments indicated that the essential catalytic cysteine residue required for the phosphatase activity of PTP-H2 was required for apoptotic activity in Sf-21 cells. Loss of adhesion was insufficient to stimulate apoptosis of Sf-21 cells. PTP-H2 expression, however, did significantly reduce proliferation of Sf-21 cells, which could contribute to the apoptotic activity of this viral gene. Overall, our results indicate that specific genes expressed by MdBV induce apoptosis of certain insect cells and that this activity contributes to immunosuppression of hosts.
pubmed:language
eng
pubmed:journal
pubmed:citationSubset
IM
pubmed:chemical
pubmed:status
MEDLINE
pubmed:month
Jun
pubmed:issn
0022-1317
pubmed:author
pubmed:issnType
Print
pubmed:volume
89
pubmed:owner
NLM
pubmed:authorsComplete
Y
pubmed:pagination
1411-20
pubmed:meshHeading
pubmed:year
2008
pubmed:articleTitle
Protein tyrosine phosphatase-H2 from a polydnavirus induces apoptosis of insect cells.
pubmed:affiliation
Department of Entomology and Center for Tropical and Emerging Global Diseases, University of Georgia, Athens, GA 30602, USA.
pubmed:publicationType
Journal Article, Research Support, U.S. Gov't, Non-P.H.S., Research Support, N.I.H., Extramural